Unpin pip version, change requests requirement

pip version was pinned to 20.2.4 but the commit log doesn't specify a
reason.

We recently had some issues with tox unable to install
dci-control-server from local copy with python 3.9.

Removing the pin allows the environment to install.

Update requests requirement to >=2.27 where JSONDecodeError has been
introduced. Newer pip version installs 2.22 required by
dci-control-server.

Change `requests.models.JSONDecodeError` to the correct
`requests.exceptions.JSONDecodeError`

Change-Id: I22164b5e98ac4ea371ae8922277912bc67531333
Depends-On: https://softwarefactory-project.io/r/c/dci-control-server/+/34324

Author: fcharlier

dciclient/diff_jobs.py

@@ -169,7 +169,7 @@ def main(argv=sys.argv, environ=os.environ):
 
     try:
         response = run(context, args)
-    except requests.models.JSONDecodeError:
+    except requests.exceptions.JSONDecodeError:
         sys.stderr.write("Invalid parameters.\n")
         return 1
     except Exception as ex:

requirements.txt

@@ -1,3 +1,3 @@
 PrettyTable>=0.7.2, <0.8
-requests>=2.6.0, <3.0
+requests>=2.27.0, <3.0
 dciauth>= 2.1.7

tests/shell_commands/test_job.py

@@ -234,7 +234,7 @@ def test_diff_jobs(runner, job_id):
 
 
 def test_diff_jobs_invalid_parameter(runner, job_id):
-    with pytest.raises(requests.models.JSONDecodeError):
+    with pytest.raises(requests.exceptions.JSONDecodeError):
         runner.invoke_diff_jobs(["--job_id_1", "toto"])
 
 

tox.ini

@@ -7,8 +7,6 @@ usedevelop = True
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 install_command = pip install -U {packages}
-setenv =
-    VIRTUALENV_PIP = 20.2.4
 passenv= *
 whitelist_externals =
     sh